Spark Plug Sealing via Controlled Compressive Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reduction in size and diameter of spark plugs for internal combustion engines complicates achieving an airtight seal between the insulator and metal shell, as excessive compressive deformation can damage the insulator, while insufficient deformation leads to poor sealing.
Innovation Solution
A method involving a metal shell with a specific crimping and compressive deformation process, where the crimping portion is formed into a crimping portion and the compressive deformation portion is pressed with a controlled constant value, using different press molds and potentially heated, to ensure precise sealing without damaging the insulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressive deformation on the metal shell is increased to improve sealing, then the sealing properties are improved, but the insulator may become damaged
Solution Approach 1:
The patent applies parameter changes by controlling the pressing amount of the press at a constant value from the start to the end of compressive deformation. This precise control of deformation parameters ensures adequate sealing while preventing excessive force that would damage the insulator. The method transforms the uncontrolled deformation process into a precisely controlled one with defined pressing amounts and timing.
2Adaptability or versatility
If the size and diameter of spark plugs are reduced to enhance design freedom, then the design flexibility is improved, but the mechanical strength of the insulator is decreased
Solution Approach 1:
The patent addresses this contradiction by changing the process parameters of compressive deformation. By controlling the pressing amount at a constant value and managing the deformation process precisely, the method enables adequate sealing in reduced-size spark plugs without exceeding the insulator's strength limits. This allows compact spark plug designs while maintaining structural integrity.
3Manufacturing precision
If the pressing amount of the press is not controlled precisely, then the manufacturing process is simpler, but the precision of compressive deformation is insufficient
Solution Approach 1:
The patent implements precise parameter control by defining a constant pressing amount from the start to the end of compressive deformation. This controlled approach ensures high manufacturing precision in the sealing process. The method balances the added control complexity with the necessary precision for reliable sealing in compact spark plugs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances the precision of the compressive deformation, securing high-sealing properties between the metal shell and insulator, preventing damage and ensuring effective gas containment in spark plugs with smaller diameters.
Implementation Method 1
pressing the crimping portion of the metal shell in an axial direction to compressively deform the intended compressive deformation portion of the metal shell and thereby seal a space between the stepped portion of the metal shell and the stepped portion of the insulator
Implementation Method 2
the step (e) is performed while the intended compressive deformation portion is being heated
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for manufacturing a spark plug which includes: (a) preparing a metal shell; (b) preparing an insulator; (c) inserting the insulator in an insertion hole of the metal shell; (d) forming an intended crimping portion of the metal shell into a crimping portion; and (e) pressing a lower side portion of the metal shell closer to a position lower than the intended compressive deformation portion, and pressing the crimping portion of the metal shell in an axial direction to compressively deform the intended compressive deformation portion of the metal shell and thus seal a space between a stepped portion of the metal shell and a stepped portion of the insulator, wherein step (e) controls a pressing amount of a press in a constant value from the start of compressive deformation to the end thereof.